Best way to confirm a good network

So i want to pitch RC to a few of my longtime customers to get them away from PRIs and into current times. I also want to make sure i have no issues with their network as 1 is a stock trading company who relies heavily on their network for speed and such. I ran a speedtest at my last customer who i switched to RC and it seemed strong enough (comcast cable business class) they now have jitter and drop call issues and their IT department isnt quite helpful in making sure ettings are correct for QoS. To avoid that issue with my next sale what steps can i take to make sure there will be 0 issues of the same kind?

Hey there. Cable is the least desirable internet type but it still can work. A lot of times you have to prove to the isp that you are dropping packets and having high jitter before they do anything. Ideally you would have a finer connection even if it's not dedicated. ATT ABF is a very reasonably priced fiber option and we have great results with it. Also, you want to make sure you have a router that can be properly configured as that is really the most important part. Sonicwalls work great and we use peplink a lot with great success too. An even more optimal solution is to have two connections and keep voip traffic on the lowest latency connection while data goes through the other or load balances between the two (do not load balance the voip traffic). Peplinks are awesome for this. The Balance One is a great option for a network of up to about 20 or so people and then you want go to the 305 and higher if larger. The fact that that it department isn't being helpful is a shame because that is truly the most important part as even coax can work well when dialed in properly.

Personally I would make sure that I.T. personnel are part of the transition team. While managers and trainers are a big part of setting up a VoIP communications system, simply running a speed test is not enough for QoS. I.T. persoonel involved from the start can begin to make sure that their routers and ports are all correctly set so there are no issues when the system goes live.

The reality is; it's not the service or the vendor, it's the serving CO. For example, I have a client with 70 users on Comcast 100/20Mg that has never had any issues in 24+ months. I have another client with 10 users on Comcast 100/20mg and constant issues. Both clients are exactly the same; same network equipment, same IT personnel, same cabling infrastructure, etc - the only difference is the serving CO. We just switched them to ATT ABF (as Andrew referenced above) on 3/1/17 and (fingers crossed) issues went bye-bye.

Besides that, choosing quality network gear that has good management and monitoring options is very helpful. If you just have a black box of a cable modem or SMB router there is very little you can do as far as troubleshooting. Cisco Meraki is a good choice and I try to pair Meraki gear with RingCentral installations for these reasons.

Meraki is super simple and has great support. Basically, besides creating a voice VLAN I just do something like this on the firewall to ensure voice has highest priority leaving the LAN (192.168.250.0/24 is my voice VLAN):

If troubleshooting, I can do packet captures easily and also look at metrics like this:

One more thing is that in some cases you may create a separate network for voice especially if the network group is uncooperative or nonexistent. This might mean separate internet service and firewall and even separate switches and cabling or at least a voice VLAN on existing switches. Still of course you can have issues if the ISP is not reliable and stable though.